Juniper® JNCIA Exam Cram Notes : Routing Engine And Packet Forwarding Engine

2. Junos OS Fundamentals

2.3 Routing Engine and Packet Forwarding Engine

The Routing Engine is the central location for control of the system in a juniper networks router and it consists of an Intel-based PCI platform running JUNOS software. The Routing Engine constructs and maintains one or more routing tables. From the routing tables, the Routing Engine derives a table of active routes, called the forwarding table, which is then copied into the Packet Forwarding Engine.

Functions of the routing engine include the following

  • Handling of routing protocol packets
  • Management Interface
  • Configuration Management
  • Accounting and alarms
  • Modular Software
  • Scalability

The Packet Forwarding Engine is the central location for data packet forwarding through the router.

  • Switching control board.
  • Flexible PIC Concentrator, and
  • Physical Interface Card

The packet forwarding engine uses four ASICs:

  • The Internet Processor ASIC
  • The I/0 Manager ASIC
  • The PIC I/0 Manager ASIC
  • The Distributed Buffer Manager ASICs.

The software upgrades and the maintenance are performed on the Routing Engine. Routing Engine is the central location that controls the system. It is often referred as the intelligence of the router.

Routing Engine is the place where the entire JUNOS software resides. It is the logical location where software is stored. Routing Protocols and routing tables are also stored in this engine.

Routing Engine 2 is found in the M-Series routers of Juniper Networks. It contains the 333MHz processor and 768MB of Random Access Memory(RAM). M-Series is the first series of router introduced by the Juniper Networks.

The main components of the Packet Forwarding Engine in the juniper devices are the Physical Interface card(PIC), the Flexible PIC Concentrator(FPC) and a switching control board. All these components consist of the ASICs designed by Juniper Networks.

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